1. 直接写出得数。
$15×\frac {4}{5}=$
$\frac {7}{9}×72=$
$6×\frac {5}{12}=$
$\frac {1}{4}×\frac {2}{3}×8=$
$6×\frac {2}{7}=$
$\frac {2}{15}×30=$
$9×\frac {5}{9}=$
$14×\frac {6}{7}×\frac {1}{3}=$
$\frac {2}{5}×\frac {10}{11}=$
$\frac {2}{9}×\frac {18}{5}=$
$\frac {2}{5}×\frac {15}{8}=$
$\frac {4}{13}×39×\frac {1}{4}=$
$\frac {1}{6}×\frac {3}{5}=$
$\frac {3}{4}×\frac {1}{2}=$
$\frac {3}{4}×\frac {5}{6}=$
$\frac {27}{44}×11×\frac {8}{9}=$
$\frac {21}{25}×\frac {5}{7}=$
$\frac {7}{16}×\frac {4}{7}=$
$\frac {2}{3}×\frac {4}{5}=$
$\frac {7}{10}×\frac {5}{14}×\frac {1}{3}=$
$\frac {1}{7}×\frac {2}{5}=$
$\frac {8}{19}×\frac {57}{56}=$
$\frac {3}{8}×\frac {7}{4}=$
$\frac {3}{40}×\frac {5}{6}×\frac {4}{5}=$

1. 12 56 $\frac{5}{2}$ $\frac{4}{3}$ $\frac{12}{7}$ 4 5 4 $\frac{4}{11}$ $\frac{4}{5}$ $\frac{3}{4}$ 3 $\frac{1}{10}$ $\frac{3}{8}$ $\frac{5}{8}$ 6 $\frac{3}{5}$ $\frac{1}{4}$ $\frac{8}{15}$ $\frac{1}{12}$ $\frac{2}{35}$ $\frac{3}{7}$ $\frac{21}{32}$ $\frac{1}{20}$

2. 计算下面各题。
$180×\frac {3}{8}×\frac {1}{6}$
$\frac {25}{56}×50×\frac {8}{15}$
$\frac {5}{3}×\frac {1}{6}×\frac {4}{15}$

2. $\frac{45}{4}$ $\frac{250}{21}$ $\frac{2}{27}$

3. 填一填。
$\frac {3}{4}×$()$=1$
$\frac {7}{2}×$()$=1$
$\frac {1}{10}×$()$=1$
()$×0.35=1$
$2.5×$()$=1$
()$×26=1$
$\frac {6}{7}×$()$=1$
$\frac {19}{11}×$()$=1$
$1\frac {5}{9}×$()$=1$

3. $\frac{4}{3}$ $\frac{2}{7}$ 10 $\frac{20}{7}$ $\frac{2}{5}$ $\frac{1}{26}$ $\frac{7}{6}$ $\frac{11}{19}$ $\frac{9}{14}$

4. 在图中表示出算式的意义。
(1)

$\frac {2}{3}×\frac {3}{5}$
(2)

$\frac {3}{4}×\frac {1}{3}$

4. (1)

(2)
(画法不唯一)